The operation of onboard electrical appliances and electrical conveniences (e.g., air conditioners, cooking ranges, microwaves, electric fans, televisions, video cassette recorders, refrigerators, freezers, coffee pot, blenders, hot water heaters, flood lighting, battery-chargers, computers, etc.) are generally limited for use by the boater while the boat is tied at a dock where electric power can be supplied by a removable shore power cable connection to the boat. However, once the boat leaves the dock, the convenient use of 120/240 VAC electric power is not available and, in addition, the boat's standard 12VDC battery system is not capable of operating these high power consuming appliances and accessories. Therefore the convenience and enjoyment of these appliances and accessories is limited only to dockside use. Thus, once the boat is underway, e.g., on the lake, or open sea, etc., some type of independent electrical power source on the boat itself is required. In fact, the marine industry has recognized that " . . . finding room for a genset can be a problem, especially in boats in the less-than-40-foot range." Motor Boating & Sailing/December 1999; p. 18, and "Mainship, like most manufacturers tries to provide as many amenities as possible that can be used when underway or at anchor. But, finding room for a genset can be a problem, especially in boats in the less than 40 foot range." Motor Boating & Sailing/December 1999.
Portable power generators, typically used at remote locations, such as campsites, cannot be used onboard boats because of their inherent hazards, such as hot exhaust gases, carbon monoxide hazard, combustion, exposure to salt water (e.g., being temporarily submerged by a wave) etc. Typically, these power generators comprise an internal combustion engine whose mechanical energy is converted into electrical energy by driving electric generators. Generators of this type use a small internal combustion engine that is air-cooled with low horsepower ratings (generally under 15 horsepower), similar to what is used in lawn mowers. In addition, the heat and fumes produced from the exhaust gases of the internal combustion engine require that the generator sets be operated outdoors in open spaces, away from any hazards. Also, the internal combustion engines must operate at continuously high RPMs to maintain the proper alternating current and voltage frequency required, typically, 50-60 Hz. Their operation produces an inordinate amount of noise and vibration. As a result, these types of generator sets are most suitable for use only outdoors where there is adequate ventilation and fresh air to cool and ventilate the unit for safe operation. In other words, these types of generators are not intended for marine applications. There have been attempts to enclose these portable air-cooled generator sets to quiet the noise produced, but the attempts have not been entirely satisfactory to quiet the noise from the internal combustion engine, muffle its exhaust system and dampen all the associated vibration of the generator set and the housing.
These portable air-cooled generating sets are not intended to be used aboard boats because of the confined space and hazards onboard a boat. Their use in confined spaces on boats introduces several risks and hazards. The hot exhaust fumes are a hazard that can burn crew members or ignite materials aboard the boat, thereby creating a fire hazard. The carbon monoxide gases from the exhaust can settle into bilges and cabin areas of the boat causing the hazard of carbon monoxide poisoning. The potential for the generator set to be exposed to water, i.e., becoming wet, splashed or even submerged while operating on a boat, can create explosive and electrical shock hazards to crew members with great risk of injury or death.
To provide electrical power onboard a boat for use away from the dock while underway, the boater's only option is to install a special inboard power generating system that is expensive, heavy, and requires large space below decks and has associated hazards of operation. These inboard power generating systems utilize an internal combustion engine to power a generator to supply large, on-demand electricity, to operate electrical appliances and accessories. This type of electrical generating system is mounted inside the boat's hull in a special compartment generally located under the boat's deck. This necessitates special installation requirements to permit safe operation because of the hazards in operating internal combustion engines in such an enclosed space. For example, in order to cool the hot engine, a raw water intake must be located below the water line through a hull fitting and a pump must be installed to circulate the raw sea water to cool down both the engine and hot exhaust gases to safe operating temperatures. This installation also requires special exhaust plumbing to safely remove dangerous hot exhaust gases through special water cooled mufflers and additional through-hull exhaust fittings; thus, the holes in the hull of the boat must be water-tight to keep water out. The use of highly combustible fuels such as gasoline in enclosed compartments requires further special safety measures. This type of a below-deck power generating system requires special vents to supply air to feed the internal combustion engine while simultaneously being water-tight to prevent water from contacting the unprotected electrical power plant during operation.
Other disadvantages are that these below-deck generators sets are themselves heavy and, therefore, increase the weight of the boat. For example, Onan, a subsidiary of Cummins Engine Company of Columbus, Ind., manufactures several marine generator sets, such as models 5.5 MDKUB/8.5 MDKUB-380 lbs.; 7.0 MDKAL/9.0 MDKAL-610 lbs.; 8.0 MDKWB/10.0 MDKWB-450 lbs. and 9.5 MDKAN/11.5 MDKAA-695 lbs. Phasor Marine, of Pompano Beach, Fla., manufacturers a marine generator set Model K3-5.5KW that weighs approximately 380 lbs.; Kohler of Kohler, Wis., manufactures a marine generator set Model 5E-5K that weighs approximately 205 pounds. One boat manufacturer, namely, Mainship of Luhrs Marine Group of St. Augustine, Fla., manufactures a boat Pilot/Pilot Sedan that utilizes a Kubota generator set (UCM1-3.5) that utilizes a single-cylinder diesel generator and that weighs approximately 160 lbs.; however, this does not include the additional weight and space required for remote muffler components (e.g., mufflers, hoses, seacocks, etc.) which also increase the overall weight. A large portion of this weight can be attributed to the iron-cast internal combustion engines used in the generator sets, as well as the elaborate muffler systems necessary for muffling the sound, and cooling the exhaust gases, of the generator-set engine. These muffler systems occupy a large space, thereby diminishing the below-deck space. Thus, this type of inboard power generating system is complex, heavy, expensive to install, subject to many safety hazards while operating and is physically limited only to larger boats usually over 36 feet in length, which have ample space below deck for such an installation. Thus, this type of below-deck electric generation installation is complex, expensive and subject to many hazards and can only be achieved where the proper below-deck space is available to meet all these safety requirements. As a result, small boats just do not provide sufficient space to safely install an electrical power generating system.
Another alternative for providing onboard electrical power is via the use of inverters that convert DC battery power into AC electrical power. However, several disadvantages also exist in using inverters. For example, the inverters are only good as long as there is battery power; once the boat's battery(ies) are depleted, the inverters are rendered useless, along with all other electrical components requiring the battery power. In addition, inverters are rather expensive, especially those required for powering appliances such as refrigerators, freezers, etc; furthermore, when inverters are used, additional batteries are required to avoid depleting the boat's batteries, thereby further increasing the cost and weight to the boat. As a result, the typical boater most likely will not invest in an inverter, knowing that its power is limited by the boat's battery(ies) power in any case.
The following U.S. patents are cited as examples of attempts to provide electrical power to onboard equipment but suffer from one or more of the problems discussed above, and/or are dependent upon the boat's propulsion device or the boat's motion.
U.S. Pat. No. 3,619,632 (Labombarde) discloses, an outboard generator unit for sailboats. The outboard generator unit comprises a housing arranged to be attached to the transom of a sailboat and including a generator. A propeller is mounted in a housing coupled via a drive shaft to the generator so that when the sailboat is moving through the water, the propeller is rotated, thereby rotating the generator and producing electricity. The electricity is then fed via cables back to a battery for the inboard propulsion system of the sailboat, that is, its engine.
U.S. Pat. No. 4,010,377 (McKenzie) discloses, a generator mounted on a propulsion unit of an outboard motor through an interposed adaptor. The adaptor includes various plug receptacles into which electrical plugs can be connected to provide electrical power to electrical appliances in the boat on which the unit is mounted. Electric power is provided thus by the operation of the propulsion motor.
U.S. Pat. No. 5,011,442 (Polcz et al.) discloses, an auxiliary power generating means for outboard motors including an alternator adapted for installation between the flywheel and the recoil starter of an outboard engine. The auxiliary power generation device includes output electrical connections for providing electrical power to electrical bold-appliances on the boat.
U.S. Pat. No. 3,812,379 (Kaufman et al.) discloses, a combination propulsion system for boats. The propulsion system is an outboard mounted unit including a gasoline engine and an electric motor and means for coupling the motor to the engine, whereby the electric motor can be reversed and uses a generator when the engine is running. In this mode of operation, the battery for the motor can be recharged.
Thus, there remains a need for an electrical generating system to provide an economical, safe, reliable, and quiet means of generating electricity for small boats independent of the boat's propulsion system and independent of the boat's motion when the boat is away from the dock and away from the convenience of shore side electrical power.